Electrolytic apparatus for the preparation of paper-pulp.



P. F. STRONG. 4 ELECTROLYTIC APPARATUS FOR THE PREPARATION OF PAPER PULP.

' APPLICATION FILED JUNE 10,1910.

Patented Apr. 15, 1913 NllTE 11%|,

STATES FFIOE;

FREDERICK F. STRONG, OF ST. PETERSBUBG, FLDRIDA.

ELECTROLYTIC APPARATUS FOR THE PREPARATION OF PAPER-PULP.

ment in l llcctrolytic Apparatus for the Preparation of Paper-Pulp, of which the following description, in connection with the accompanying drawings, is a specific-a 'tion, like letters on the drawings represen ting lihe arts.

My invention is an apparatus for the electrolytic treatment of plants, tissue, etc., in the manufacture of pulp therefrom, from which paper may be made or artificial hard rubber, ivory, vulcanized fiber' and various other finished products.

One object of my invention is to provide means for the disruptiomseparation and isolation of the cellulose ultimates by partially saponitying the oils and resinous binding material.- This is accomplished inithe absence of heat, or in other words, I provide means capable of handling the material and producing the desired results cold and at the ordinary atmospheric pressure, one

resulting advantage bein that the resins are only partially remove a portion thereof being left, winch in the subsequent manufacture therefrom of paper, for instance, under the-hot rolls of the paper machine serves to bind the same together into a tough web, producing in other words a self-sizing paper. This is especially the case with palmotto stock, which is unusually rich in resirb one binding material.

I have aimed to eliminate to allarge extent the use of chemicals, especially strong chemicals, heretofore commonl used in the manufacture of wood pulp an the like, my object being also to produce What may be termed a textile-fiber-pulp,similar in quality to that obtained from new linen rags.

A further object is to produce a non-hygro-scopic pulp whereby it at once pa ts with its water on the paper machine, avoid-- 'ing the extreme difliculty at present expo rienccd in treein ordinary pulps from their water content, urthermore, ulp produced ashreiha/fter explained is extremely light in weight and felts. so readily and intimately that longer fibers may be used in, making the pulp than would otherwise-be possible, thereby giving the resulting paper the durability of a finely woven fabric. The

Specification of Letters Patent.

Application filed June 10, 1910.

proces such is described at length and Patented Apr. 15, 1913.

Serial No. 586,219.

claimed in a copcnding application Serial No. 566,220, filed June 10, 1910. 7

My electrolytic apparatus provides means for a continuous flow of the pulp solution in the presence of but separated from a'modcratcly strong salt solution. Thepassage for the flow of the pulp has porous walls, inwhich 'I' provide at frequent intervals suit able electrodes,preferably carbon, around which the pulp solution flows, said passage being preferably made up of a series of porous jars having connecting passages alternately at their tops and bottoms. These jars or porous passages are arranged in two sets, one connected to the negative pole and i the other to the positive pole of the source of energy. The pulp in passing from one set of jars or passage to the other, is treated in a series of settllng and agitating tanks, all as will be more fully explained and better understood from the following descrip tion taken in connection with the accompanying drawings, in which I have shown a preferred embodiment of the invention,

Fig. '1 showing the apparatus in topplan;

and Fig. 2 in side elevation, partly broken away and sectioned for clearncss of illustration.

In a tank 1 lined or composed of acid and alkali-proof material and filled nearly to the top with moderately strong salt solution 2 are immersed two pulp-solutionconveyers- 4, each herein shown as composed of a series of porous jars 5 of clay or unglazed porcelain, joined alternately at top and bottom by tubes 6, 7, preferably of similar material. In each of these jars is an electrode, preferably a fluted and transversely apertured carbon 8 attached to an insulating cover 9 fitting tightly in the mouth of the jar and provided with a suitable binding post or terminal connection 10 for connecting the carbon with the conductor wires 11, 12, deriving current from a battery or other suitable source, herein shown for convenieiice as a generator 13 of continuous current. All

the electrodes of the jars in the tortuous pipe or passage 3 are connected in parallel to the negative pole of the dynamo and the terminals of the jars in the tortuous pipe or passage 4 are connected in parallel to the positive pole of the dynamo, The current passes through the orous walls of the jars ut the solutionsw iich carry the pulp-material db not'pass therethrough to mingle with the solution in the large tank, The

. with stron pulp solution enters through an inlet pipe 14, flows through the porous tubular menr the soda solution, the latter being drawn oil through a drainage pipe 19. A strainer .20 holds back the pulp, which is kept somewhat agitated by a stirrer 2],, washing 'water being introduced through a pipe 22. When thoroughly .washed, the pulp is permitted to flowinto a concentrator and collecting tank 23 where it is treated a second time salt solution admitted through a pipe 24. the previous strong salt solution having been mixed with the pulp prior to its entrance at 14) and is thence elevated through a pipe 25 by any suitable means as a pump 26 and delivered through the pipe 16 to the pipe or passage 4; and its positive electrodes and jars for the bleaching process.

In use, the crude pulp which has previously been Washed and mixed with strong salt solution in a suitable mixer or kneader andthen diluted with a large volume of salt solution somewhat less dense than that used in the mixer, is caused to pass in a continuous stream through the row of jars, (5., through the tortuous conduit or passage 3 where the pulp is refined both mechanically and chemically by the action of the liberated hydrogen and the caustic soda. The cathode electrolysis of the brine liberates minute bubbles of hydrogen gas in and arbund the interstices of the pulp body which is against the cathodes, and these bubbles, together with the electrical activity, tend to burst apart or loosen the small fibers and cell masses, rendering them easily separable by subsequent treatment, aided of course by the chemical products of the electrolysis. The caustic soda whlch is simultaneously formed still further effects the isolation of the cellulose ultimates by partially saponifying the oils and resins. Especial attention is di-rected to the fact that this is a partial saponification. .As' the treatment is cold and at ordinary atmospheric pressure, there is only a partial I solution or removal of the oils and resins, previously stated. The peculiar "nature of the plant material, the finely divided and actually dis sected cellular bits,and the bringing thereof, when impregnated. with brine as the only source of the chemical agents, into (llrect 1n- .timate contact with the electrodes, in the cold, without pressure, permits the disruptive action n'ientioned. The partially. loosened cells of the dissected mass have an electrically conductive film in the surfaces electrolysis actually occurs and the hydro-- as well as the. cellular tissue or pulpy part and crevicesof the pulp bits because their cell walls have been osmotically impregnated with salt, and, as the spaces or passages for said cellular mass in the series of electrode chambers, between the porous walls of the electrode surfaces, issmall, the pulp'bits atsome point of their passage are' sure to make contact with thee'lect'rodes and become temporarily extensions or conducting branches of said electrodes, so that the gen/bubbles and caustic soda are actually formed or liberated on the surface and in the interstices of the bits of pulp which are against the electrodes. Having thus effected thev subdividing and disintegrating of the cell-masses, etc., and the isolation of the cellulose ultimates as stated, the crude pulp mass is now ready for the bleaching process by nascent chlorin gas] The pulp at this stage is nearly white and consists of practically pure cellulose almost entirely free from ligni'n, the substance which causes the rapid rotting or deterioration of papers made from wood pulp. After emergin from the negative jars the pulp, suspended v in a solution rich in caustic soda, is freed therefrom 'by the settling and washing op eration in the tank 8 and is then againtreated to a strong'salt solution in the tank 28 and passed alongby the circulation pump 26 to the jars of the passage l where the anode electrolysis current evolves therefrom nascent chlorin, which bleaches and whitens the pulp as it flows continuously along, thereby decolorizing any remaining green matter retainedin the pulp cells: After leaving the tank, the pulp is thoroughly .washed in fresh water and may then be run into sheets, dried, baled and shlpped to the paper mills the same as is now done with sulfite pa er pulp from wood, or it can be run into an ordinary beating engine and treated so as to be at once made into paper without intermediate drying. The passages 3 and 4 are preferably made of sufiicientr capacity and length of joints or turns ,to handle the fibrous portion of the plant stock thereof, if desired, and it will be understood that instead of making the passage tortuous. it can be straight, the former being prefer able for supporting the electrodes and avoid ing a long tank. In the case of relatively long fibers, the large structural fibers are readily broken up when the caustic soda solution-containing them reaches the washing tank. so that they are delivered therefrom in the form of small, fine, silky fibers suitable for spinning.

As'already mentioned, besides the advantage of strength and non-rotting, already mentioned, I have also mentioned the fact that the resultant paper is practically selfsizing, due to the retention in the pulp of a suficient portion of the natural resinous ma terial thereof for this purpose. Another pcculiarity of the paper made by my process and apparatus is the readiness with which the pulp parts with its water on the paper machine, 6., its non-hygroscopic character.

In other papers the prolonged treatment in' the beating and refining engine not only breaks up the ultimate libel-s but renders them watensoaked so that great dilliculty is experienced in freeing ordinary papers from the contained water. My process is intended to deal primarily with such raw materials as the cabbage palm or palmetto, the'saw pal-,- metto, the everglade saw grass, the century plant, plantain, New Zealand flax; Adams' needle, Spanish bayonet, pineapple, banana,-

and other inside-growers (although not limited thereto) inwhich the ultimate fibers are pointed with the very small lumcns naturally closed and the fiber naturally more or less water-proof. Hence by eliminating the digestion and the refining-engine treatment and providing means which leaves a suiticient amount of this insoluble resin coating or waterproof covering to size the paper and bind together the small fibers, the result is that the web of paper is practically n'onhygroscopic, and whatever water or moisture is carried along mechanically therein is readily parted with on the paper machine.

Als o'the resulting paper is extremely light in weight and because of its longer fibers and its non-rotted or decomposed condition it has extreme durability, approximatiue that of a finely woven fabric. Practically all the usual chemical baths and processes commonly employed 'in paper manufacture are eliminated and the slight chemical action required for the refining and bleaching of the pulp is liberated electrolytically from a solution of common salt or sea-water. Thisis possible because the pulp material is not only brought to the apparatus in as nearly as possible its original structural. elements but the active power of the chemicals is enormously increased by the fact that the latter are liberated in a nascent condition and in intimaterelation with the plant cells and small fibers thereby as already explained. producing the combined mechanical and chemical effect, the mechanical effect being to disrupt or subdivide the mass by the generated gas bubbles and the chemical cf feet being to further free the cellulose.

Before entering upon the electrolytic portlon of the process, the pulp or prepared plant-material or half-stuff is thoroughly impregnated with a strongsolutiou of salt. Having thus filled the material with a strong salt solutidn, it; is suspended in a weaker salt solution and then conducted through the electrolytic chaniicls. As a strong salt solution is a better conductor of electricity than a'weak salt solution, it results that as the libersthus impregnated with salt are con veycd in a weaker salt solution past the cathode electrodes in the conveyor 3, said libers brush against the electrode surfaces, so that the electrolysis at that moment aii'crrts the cells and fiber elements of the bits of pulp which are in direct contact with said electrodes. Then having: by this means pro duced the mechanical disintegration and chemical disintegration of the fibrous ele ments, as previously explained in detail, the

mass is washed thoroughly free of its caustic soda before being subjected to the bleaching process. This is necessary in order that the bleaching process may be effective. Having been washed thoroughly and thereby freed of its caustic soda, the cleaned fibers are again impregnated with a strong salt solution, so that when it then passes through the bleaching conveyor the electrolytic action is primarily a bleaching), action. The chloriu expends itself in bleaching the fiber rather .than in combining with any free alkali,

which would be the case if the caustic soda had not been removed.

Having described my invcntion, what I claim as new and desire to secure by Lctters Patent is, I 1

1. An apparatus of the kind described,

comprising supporting means for subdivided plant-material in liquid form, combined with means including electrolytic means including cathodes supported at one end only so as to extend freely into direct. contact with the liquid on all sides excepting said end to disrupt the fibers and cellmasses of the plant material and form thcrcin caustic soda For the further isolation of the cellulose constituents of the plant-inal'crial.

An apparatus hf the kind described, comprising a supporting conduit for suhdividcd plant-material in liquid form, comhiued with electrolytic means extending into i thereafter washing'out the chemicals from a thetreated plant-material, separate elcctro- I iytic means for immediately thereafter bleaching the previously washed plant-material as it continues to flow along, and

. containing said tube and provided with-anelectrolyte to surround said tube, an electrode mounted Within said tube to convey current to the subdivided plant-material flowing therethrough, and external electrie11 connections for supplying current to said electrode. 1 1.

5. An apparatus of the kind described, comprising a series of porous jars and tubular means connecting the same in series to form a continuous passage for the-fiow of subdivided plant-material, a tank provided With an. electrolyte surrounding said jars,

electrodes mounted Within said jars, and a' current conductor connecting said electrodes 'in parallel.

6. An apparatus of the kind, described,

comprising a series of porous jars and tubu lar means connecting the'same in series alternately at the top and bottom of the jars to form a-continuous passage for the flow of subdivided plant-material, a tank provided with an electrolyte surrounding said jars, electrodes mounted within said jars, and a current conductor connecting said electrodes in parallel.

In testimony vvhereof, I have signed name to this specification, in the'presence of two subscribing witnesses.

FREDERICK F. STRONG. Witnesses GEO. H. MAXWELL M. J. SPALDING. 

